Population and survival trends of Wandering Albatrosses (Diomedea exulans) breeding on Macquarie Island

Abstract

Wandering Albatrosses (Diomedea exulans) are globally threatened owing to declines in populations, and the breeding population of Macquarie Island is particularly vulnerable as it comprises fewer than 20 breeding pairs. We describe population trends of Macquarie Island Wandering Albatrosses between 1955 and 2004, combining long-term population data with demographic data collected between 1995 and 2004. Rates of annual breeding effort and survival varied markedly over time and breeding numbers declined from a peak in 1968 to near extinction in the mid-1980s. Underlying this decline was a significant decrease in juvenile survival and, to a lesser extent, adult survival. These changes in survival coincided with changes in long-line fishing effort in the Southern Ocean. Breeding numbers slowly recovered on Macquarie Island through the late 1980s and 1990s, reaching a total of 19 breeding pairs in the mid-1990s. The population remained at about this level in 2004. Relative trends in numbers and survival in the population are similar to those observed in other populations in the Indian Ocean, including Marion Island and Iles Crozet.